PROJECT SUMMARY/ABSTRACT: Suffering from chronic pain imposes substantial individual and societal burden. To combat this suffering, the long-term use of prescription opioids in the US has markedly increased. However, the long-term treatment of pain with opioid analgesics carries substantial risks, particularly when used at higher doses. These risks include overdose, abuse and addiction, depression, fractures, motor vehicle accidents, cardiovascular events (including myocardial infarction). Recent reviews indicate these harms are dose-related, with studies showing dramatic increases at opioid intake levels exceeding 120 morphine equivalents per day (MED), and concerning increases in harms even at 50 MED. To address the substantial clinical concerns associated with prescription opioid medications, Kaiser Permanente Northwest (KPNW) implemented a pharmacist-led initiative to assist primary care providers (PCP) in tapering patients on long-term, high-dose opioids. After some initial training, PCPs refer their patients to a pharmacist-led team that includes nurses and social workers. Using telephone-based outreach and communication skills including motivational interviewing techniques, the team establishes rapport with patients and coaches them on strategies to lowering their opioid consumption and advises on non- pharmacologic pain treatment. The interactions can take weeks and multiple phone calls. We propose to evaluate this unique natural experiment, and preliminary evidence suggests remarkable success of the program. We propose a mixed-methods study, using the RE-AIM framework as a guiding principle, to fully evaluate the effectiveness and generalizability of this innovative opioid tapering program. The RE-AIM framework recognizes that future adaptation by other health systems is dependent not only on program effectiveness, but also includes an assessment of the program?s reach, adoption, implementation (including costs of the program) and maintenance. We believe that efforts to reduce opioid use must be studied at the health system level due to patients? ability to seek other prescribers; our proposal and setting allows such an assessment. We propose to use strong, quasi-experimental time-series analysis to assess the effects of this unique program. Studying this clinical program using a randomized trial would be far more costly and lengthy and would lack generalizability due to selection bias among patients agreeing to participate. Results from our careful analysis of this innovative program will address important and timely questions concerning strategies for opioid taper, address an urgent public health need, and open new avenues for research.